544 Vol II 2010 en

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2010 edition

www.wmo.int

Manual on the Global Observing System

Volume II – Regional Aspects

WMO-No. 544

MANUAL ON THE GLOBAL OBSERVING SYSTEMWMO-No. 544

P-OBS_92075

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Manual on the

Global Observing System

Volume II Regional Aspects

WMO-No. 544

2010 edition

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The material contained in Volume II does not form part of the WMO Technical Regulations and is applicable only to the Members of the regional associations concerned. The words “shall” and

“should” mentioned in this volume have their dictionary meanings and do not have the regulatory character mentioned in the introduction to the WMO Technical Regulations (WMO-No. 49).

WMO-No. 544

© World Meteorological Organization, 2010

The right of publication in print, electronic and any other form and in any language is reserved by WMO. Short extracts from WMO publications may be reproduced without authorization, provided that the complete source is clearly indicated. Editorial correspondence and requests to publish, reproduce or translate this publication in part or in whole should be addressed to:

Chair, Publications Board

World Meteorological Organization (WMO)

7 bis, avenue de la Paix Tel.: +41 (0) 22 730 84 03

P.O. Box 2300 Fax: +41 (0) 22 730 80 40

CH-1211 Geneva 2, Switzerland E-mail: [email protected] ISBN 978-92-63-10544-8

NOTE

The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of WMO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries.

Opinions expressed in WMO publications are those of the authors and do not necessarily reflect those of WMO.

The mention of specific companies or products does not imply that they are endorsed or recommended by WMO in preference to others of a similar nature which are not mentioned or advertised.

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1 . REGION I – AFRICA . . . . I-1 1.1 Regional Basic Synoptic Network of surface and upper-air observing stations . . . I-1 1.1.1 Composition of the Regional Basic Synoptic Network . . . I-1 1.1.2 Criteria for inclusion of stations in the Regional Basic Synoptic Network . . . I-1 1.1.3 Arrangements and procedures for updating and amending the Regional Basic

Synoptic Network . . . I-2 1.2 Regional Basic Climatological Network of surface and upper-air observing stations . . . I-2 1.2.1 Composition of the Regional Basic Climatological Network . . . I-2 1.2.2 Arrangements and procedures for updating and amending the Regional Basic

Climatological Network . . . I-2 1.3 Regional arrangements and procedures for observations . . . I-3 1.3.1 Pressure-reduction method . . . I-3 1.3.2 Regional comparison of barometers . . . I-3 1.3.3 Ground weather radar observations . . . I-3 1.3.4 Regional Instrument Centres . . . I-3 1.3.5 Regional Radiation Centres . . . I-3 1.4. Aircraft meteorological data relay programme . . . I-3 1.5 Global Climate Observing System . . . I-3

2 . REGION II – ASIA . . . II-1 2.1 Regional Basic Synoptic Network of surface and upper-air observing stations . . . II-1 2.1.1 Composition of the Regional Basic Synoptic Network . . . II-1 2.1.2 Surface synoptic observations . . . II-1 2.1.3 Upper-air synoptic observations . . . II-1 2.1.4 Principles to be applied when revising the Regional Basic Synoptic Network . . . II-1 2.1.5 Arrangements and procedures for updating and amending the Regional Basic

Synoptic Network . . . II-1 2.2 Regional Basic Climatological Network of surface and upper-air observing stations . . . II-2 2.2.1 Composition of the Regional Basic Climatological Network . . . II-2 2.2.2 Arrangements and procedures for updating and amending the Regional Basic

Climatological Network . . . II-2 2.3 Regional arrangements and procedures for observations . . . II-2 2.3.1 Pressure-reduction method . . . II-2 2.3.2 Regional comparison of barometers . . . II-2 2.3.3 Ground weather radar observations . . . II-3 2.3.4 Regional Instrument Centres . . . II-3 2.3.5 Regional Radiation Centres . . . II-3 2.4 Global Climate Observing System . . . II-3

3 . REGION III – SOUTH AMERICA . . . III-1 3.1 Regional Basic Synoptic Network of surface and upper-air observing stations . . . III-1 3.1.1 Composition of the Regional Basic Synoptic Network . . . III-1 3.1.2 Criteria for inclusion of stations in the Regional Basic Synoptic Network . . . III-1 3.1.3 Arrangements and procedures for updating and amending the Regional Basic

Synoptic Network . . . III-2

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MANUAL ON THE GLOBAL OBSERVING SYSTEM iv

Page 3.2 Regional Basic Climatological Network of surface and upper-air observing stations . . . III-2 3.2.1 Composition of the Regional Basic Climatological Network . . . III-2 3.2.2 Arrangements and procedures for updating and amending the Regional Basic

Climatological Network . . . III-2 3.3 Regional arrangements and procedures for observations . . . III-3 3.3.1 Pressure-reduction method . . . III-3 3.3.2 Regional comparison of barometers . . . III-3 3.3.3 Ground weather radar observations . . . III-3 3.3.4 Regional Instrument Centres . . . III-3 3.3.5 Regional Radiation Centres . . . III-3 3.4 Global Climate Observing System . . . III-3

4. REGION IV – NORTH AMERICA, CENTRAL AMERICA AND THE CARIBBEAN . . . IV-1 4.1 Regional Basic Synoptic Network of surface and upper-air observing stations . . . IV-1 4.1.1 Composition of the Regional Basic Synoptic Network . . . IV-1 4.1.2 Surface synoptic observations . . . IV-1 4.1.3 Upper-air synoptic observations . . . IV-1 4.1.4 Principles to be applied when revising the Regional Basic Synoptic Network . . . IV-1 4.1.5 Arrangements and procedures for updating and amending the Regional Basic

Synoptic Network . . . IV-1 4.2 Regional Basic Climatological Network of surface and upper-air observing stations . . . IV-2 4.2.1 Composition of the Regional Basic Climatological Network . . . IV-2 4.2.2 Arrangements and procedures for updating and amending the Regional Basic

Climatological Network . . . IV-2 4.3 Regional arrangements and procedures for observations . . . IV-2 4.3.1 Pressure-reduction method . . . IV-2 4.3.2 Regional comparison of barometers . . . IV-2 4.3.3 Ground weather radar observations . . . IV-2 4.3.4 Regional Instrument Centres . . . IV-3 4.3.5 Regional Radiation Centres . . . IV-3 4.4 Global Climate Observing System . . . IV-3

5. REGION V – SOUTH-WEST PACIFIC . . . V-1 5.1 Regional Basic Synoptic Network of surface and upper-air observing stations . . . V-1 5.1.1 Composition of the Regional Basic Synoptic Network . . . V-1 5.1.2 Surface synoptic observations . . . V-1 5.1.3 Upper-air synoptic observations . . . V-1 5.1.4 Principles to be applied when revising the Regional Basic Synoptic Network . . . V-1 5.1.5 Arrangements and procedures for updating and amending the Regional Basic

Synoptic Network . . . V-1 5.2 Regional Basic Climatological Network of surface and upper-air observing stations . . . V-2 5.2.1 Composition of the Regional Basic Climatological Network . . . V-2 5.2.2 Arrangements and procedures for updating and amending the Regional Basic

Climatological Network . . . V-2 5.3 Regional arrangements and procedures for observations . . . V-2 5.3.1 Pressure-reduction method . . . V-2 5.3.2 Regional comparison of barometers . . . V-2 5.3.3 Ground weather radar observations . . . V-2 5.3.4 Regional Instrument Centres . . . V-3 5.3.5 Regional Radiation Centres . . . V-3

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CONTENTS v Page 5.4 Other in situ observing systems . . . V-3 5.4.1 Marine observations . . . V-3 5.4.2 Aircraft meteorological data relay programme . . . V-3 5.4.3 Space-based observations . . . V-3 5.5 Global Climate Observing System . . . V-3

6. REGION VI –EUROPE . . . VI-1 6.1 Regional Basic Synoptic Network of surface and upper-air observing stations . . . VI-1 6.1.1 Composition of the Regional Basic Synoptic Network . . . VI-1 6.1.2 Criteria for inclusion of stations in the Regional Basic Synoptic Network . . . VI-1 6.1.3 Arrangements and procedures for updating and amending the Regional Basic

Synoptic Network . . . VI-2 6.2 Regional Basic Climatological Network of surface and upper-air observing stations . . . VI-2 6.2.1 Composition of the Regional Basic Climatological Network . . . VI-2 6.2.2 Arrangements and procedures for updating and amending the Regional Basic

Climatological Network . . . VI-3 6.3 Regional arrangements and procedures for observations . . . VI-3 6.3.1 Pressure-reduction method . . . VI-3 6.3.2 Regional comparison of barometers . . . VI-3 6.3.3 Ground weather radar observations . . . VI-3 6.3.4 Regional Instrument Centres . . . VI-3 6.3.5 Regional Radiation Centres . . . VI-3 6.4 Other in situ observing systems . . . VI-4 6.4.1 Marine observations . . . VI-4 6.4.2 Aircraft meteorological data relay programme . . . VI-4 6.4.3 Space-based observations . . . VI-4 6.5 Global Climate Observing System . . . VI-4

7. THE ANTARCTIC . . . VII-1 7.1 Basic Synoptic Network of surface and upper-air observing stations in the Antarctic . . . VII-1 7.1.1 Composition of the Basic Synoptic Network in the Antarctic . . . VII-1 7.1.2 Surface synoptic observations . . . VII-1 7.1.3 Upper-air synoptic observations . . . VII-1 7.1.4 Arrangements and procedures for updating and amending the Basic Synoptic

Network in the Antarctic . . . VII-1 7.2 Basic Climatological Network of surface and upper-air observing stations in the Antarctic . . . . VII-1 7.2.1 Composition of the Basic Climatological Network in the Antarctic . . . VII-1 7.2.2 Arrangements and procedures for updating and amending the Antarctic Basic

Climatological Network . . . VII-2 7.3 Weather reporting by traverse parties . . . VII-2 7.4 Automatic weather stations in the Antarctic . . . VII-2 7.5 Aircraft reports . . . VII-2 7.6 Additional and extended observations . . . VII-2

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1. The material contained in Volume II does not form part of the WMO Technical Regulations and is applicable only to the Members of the regional associations concerned. The words

“shall” and “should” mentioned in this volume have their dictionary meanings and do not have the regulatory character mentioned in the introduction to Volume I and in the Introduction to the WMO Technical Regulations (WMO-No. 49).

2. Volume II is divided into sections corres ponding to the six Regions of the World Meteorological Organization and the Antarctic, namely:

Region I Africa Region II Asia

Region III South America

Region IV North America, Central America and the Caribbean

Region V South-West Pacific Region VI Europe

Antarctic

3. Each of the sections mentioned in paragraph 2 above is based on the resolution adopted by the regional association concerned and, as regards the Antarctic, by the Executive Council in the field of the Global Observing System.

INTRODUCTION

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1.1 REGIONAL BASIC SYNOPTIC NETWORK OF SURFACE AND UPPER-AIR OBSERVING STATIONS 1.1.1 Composition of the Regional

Basic Synoptic Network

1.1.1.1 The Regional Basic Synoptic Network (RBSN) of surface and upper-air observing stations is reviewed and revised at each session of the Association. The list of stations constituting the current RBSN is given in the report of the most recent session of the Association. Changes are announced in the monthly Operational Newsletter issued by the Secretariat (see 1.1.3 below).

1.1.1.2 Manned surface land stations included in the RBSN shall conform to the specifications laid down for land stations in Volume I of this Manual.

1.1.2 Criteria for inclusion of stations in the Regional Basic Synoptic Network 1.1.2.1 Definition of the criteria

For the definition of the criteria, two types of requirements are distinguished:

(a) Target requirements (TRQs) refer to desired characteristics of network stations;

(b) Minimum requirements (MRQs) refer to threshold characteristics which are decisive for inclusion or exclusion of a station.

The inclusion of a station in the network implies a clear commitment by the Member concerned to make fair efforts for (maintaining) compliance with the TRQs.

In the table below, TRQs and MRQs for RBSN stations are recorded.

1.1.2.2 Classification of stations

Stations are classified according to their perform- ance with reference to the requirements in 1.1.2.1 above:

(a) Those stations meeting all TRQs are classified as OK;

(b) Those stations meeting all MRQs are classified as IP (incomplete programme);

(c) Operational stations not meeting all MRQs are classified as BC (below criteria);

(d) Silent stations are classified as NO (not operating).

1. REGION I AFRICA

TRQ Surface MRQ Surface TRQ Upper-air MRQ Upper-air Parameters

(measured and recorded)

Pressure Temperature Wind Humidity Weather Visibility Cloud cover Cloud base

Pressure Temperature Wind

(not for buoys) Humidity (not for buoys)

Pressure/

geopotential Temperature Wind Humidity

Pressure/

Level Surface Surface Up to 10 hPa Up to 100 hPa

Observations at main

hours UTC 4 3 2 (at 0000 and

1200) 1 (at 1200)

Observations at main and intermediate hours (i.e., 3 hourly)

8 5 – –

Availability of data 100% 50% 100% 50%

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MANUAL ON THE GLOBAL OBSERVING SYSTEM I-2

1.1.2.3 Horizontal distribution of surface stations

(a) As an ideal target over land areas, the RBSN should have a horizontal resolution of 150 km for surface and 250 km for upper-air stations;

(b) As an optimal target over land areas, the RBSN should have a horizontal resolution of 250 km for surface and 500 km for upper-air stations;

(c) OK stations are acceptable if at a distance of at least 60 km from the nearest network station.

1.1.2.4 Application of the criteria

The criteria are developed and revised periodically by the Association at each of its sessions, which take place every four years. These criteria should ensure a network with an optimum composition regarding the observing programme, reliability of reception and spacing of stations. In particular, the criteria should allow for the inclusion of stations with reduced observing programmes in data-sparse areas.

1.1.3 Arrangements and procedures for updating and amending the Regional Basic Synoptic Network Certain minor changes in the RBSN of surface and upper-air stations that do not affect the data requirements of the Region as a whole are inevit able. To provide a simple and rapid means of effecting changes proposed by the Members concerned, the following procedure shall be followed:

(a) The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of RBSN stations without formal consultation with the Members of the Association, it being understood that any change of substance, that is, one adversely affecting the density of the network or proposing a significant change in observational hours, would still require the formal agreement of Members through the adoption of a resolution by postal ballot;

(b) The Secretary-General shall notify all Members of WMO through the Operational Newsletter or by circular letter of changes agreed with the president of the Association;

(c) Each Member of the Association is encouraged to nominate a national focal point for WMO on operational matters related to the RBSN.

The nominated national focal point should coordinate information with the chair of the respective subsidiary body of the Association and the Secretariat with a view to timely updating information regarding the RBSN.

1.2 REGIONAL BASIC CLIMATOLOGICAL NETWORK OF SURFACE AND UPPER-AIR OBSERVING STATIONS 1.2.1 Composition of the

Regional Basic Climatological Network

1.2.1.1 The Regional Basic Climatological Network (RBCN) was established by the Association to provide a comprehensive network of CLIMAT reporting stations. It is based primarily on RBSN stations and includes all Global Climate Observing System (GCOS) Surface Network (GSN) and GCOS Upper-air Network (GUAN) stations, regardless of whether these report CLIMAT or not. The RBCN also includes all other stations that report CLIMAT needed for description of regional climate features, except those that are within 60 km of another network station. These other stations should be selected under the same criteria used for GSN stations. Non-RBSN stations reporting CLIMAT messages should be considered, particularly those with long records, as well as any Reference Climatological Stations.

1.2.1.2 The RBCN of surface and upper-air observing stations is reviewed and revised at each session of the Association. The list of stations constituting the current RBCN is given in the report of the most recent session of the Association.

Changes are announced in the monthly Operational Newsletter issued by the Secretariat (see 1.2.2 below).

1.2.1.3 Members are urged to comply fully with the global and regional coding procedures and data-collection standards in accordance with procedures laid down in the WMO Technical Regulations (WMO-No. 49), Manual on Codes (WMO-No. 306), Manual on the Global Telecommunication System (WMO-No. 386) and in this Manual when operating the RBCN stations.

1.2.2 Arrangements and procedures for updating and amending the Regional Basic

Climatological Network

The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of RBCN stations without formal consultation with the Members of the Association, following similar procedures to those specified for the RBSN.

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REGION I – AFRICA 1.3 REGIONAL ARRANGEMENTS AND

PROCEDURES FOR OBSERVATIONS

1.3.1 Pressure-reduction method

1.3.1.1 According to this Manual, Volume I, Part III, Regulation 3.3.2.6, the atmospheric pressure at a station shall be reduced to mean sea level, except at those stations where the resolutions of the Association prescribe otherwise (see the Manual on Codes (WMO-No. 306), Volume II, Region I, Section A.1, 1/12.1.1).

1.3.1.2 The Association has not taken any decision regarding the introduction of a uniform method of pressure reduction throughout the Region and Members of the Region are free to use the method that suits them best.

1.3.2 Regional comparison of barometers

1.3.2.1 Each Member in the Region should ensure that the barometer of each observing station in its territory is traceable to a fixed national barometric standard, through an appropriate series of comparisons at least once every two years.

1.3.2.2 National barometric standards should be traceable to an absolute barometric standard recognized by WMO, within or outside the Region, through an appropriate intercomparison at least every 10 years.

Note: The term “barometric standard” is used rather than “standard barometer”, as often the standard is not a barometer, for example, a dead weight tester is a pressure standard, but not a barometer.

1.3.3 Ground weather radar observations

Considering the usefulness of exchanging, on a bilateral or multilateral basis, meteorological information obtained by ground weather radar stations, Members are urged to continue their efforts to install ground weather radar stations for detecting precipitation, including heavy rain, hail and other severe weather phenomena, and to exchange on a bilateral or multilateral basis the meteorological information so obtained using the appropriate WMO code form, for example, FM 94-XIV BUFR.

1.3.4 Regional Instrument Centres 1.3.4.1 Considering the need for regular calibration and maintenance of meteorological instruments to meet increasing needs for high-quality

meteorological and hydrological data, the requirements of Members in the Region for standardization of meteorological measurements, the need for international instrument comparisons and evaluations, and for training of instrument experts, the Regional Instrument Centres should be established according to the Guide to Mete orological Instruments and Methods of Observation (WMO-No. 8), Part I, Chapter 1, Annex 1.A.

1.3.4.2 The instrument centres in Algiers, Gaborone, Cairo and Nairobi are designated as Regional Instrument Centres.

1.3.5 Regional Radiation Centres

1.3.5.1 Considering the usefulness of the calibration of national and regional standard pyrheliometers against pyrheliometers of the World Standard Group at five-year intervals for guaranteeing the high quality of radiation data and noting Resolution 11 (EC-XXX) – National, Regional and World Radiation Centres, Regional Radiation Centres should be established according to the Guide to Meteorological Instruments and Methods of Observation (WMO-No. 8), Part I, Chapter 7, Annex 7.C.

1.3.5.2 The radiation centres in Tamanrasset (Algeria), Cairo, Lagos (Nigeria), Khartoum, Tunis and Kinshasa are designated as Regional Radiation Centres.

1.4. AIRCRAFT METEOROLOGICAL DATA RELAY PROGRAMME

Facing the degradation of the state of the network of upper-air stations in Africa, and in order to significantly increase the number of upper-air reports for the purpose of improving forecast quality, each Member of the Association is requested to urge its national airlines to join a regional or sub regional aircraft meteorological data relay (AMDAR) programme.

1.5 GLOBAL CLIMATE OBSERVING SYSTEM

A summary of best practices involved in discharging the commitments made by the Member concerned regarding GCOS surface and upper-air stations is included in this Manual, Volume I, Part III, Regulation 2.9 (for GSN stations) and Regulation 2.10 (for GUAN stations).

I-3

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2.1 REGIONAL BASIC SYNOPTIC NETWORK OF SURFACE AND UPPER-AIR OBSERVING STATIONS 2.1.1 Composition of the

Regional Basic Synoptic Network

2.1.2 Surface synoptic observations All surface stations included in the RBSN should make surface observations at the four main standard times of observation, that is, 0000, 0600, 1200 and 1800 UTC, and at the four intermediate standard times of observation, that is, 0300, 0900, 1500 and 2100 UTC. Any surface station that cannot carry out the full observational programme should give priority to carrying out the observations at the main standard times.

2.1.3 Upper-air synoptic observations 2.1.3.1 All upper-air stations included in the RBSN should carry out radiosonde and radiowind observations at 0000 and 1200 UTC, and radiowind observations at 0600 and 1800 UTC. The radiosonde/radiowind observations carried out at 0000 and 1200 should reach the 30 hPa level for 50 per cent of the ascents. Carrying out the radiowind observations at 0000 and 1200 UTC should receive priority over the radiowind observations at 0600 and 1800 UTC.

2.1.3.2 Radiowind stations in the areas affected by tropical cyclones should, during the cyclone season, also make radiowind observations at 0600 and 1800 UTC, which should reach as far as practicable the 70 hPa level.

2.1.4 Principles to be applied when revising the Regional Basic Synoptic Network

The following principles should be applied when revising the RBSN:

(a) As a target over land areas, the RBSN should have a horizontal resolution of 150 km for surface and 250 km for upper-air stations;

(b) If an RBSN station was “silent” according to monitoring results and another RBSN station located nearby (less than 100 km for surface stations) had regularly reported its observation, the “silent” station should be replaced in the RBSN. If there is no alternative regularly reporting station nearby, the “silent” station may remain on the list if there is an intention to restore operations;

(c) In data-sparse areas existing stations may be nominated for the RBSN even if there are no plans for them to carry out the full schedule of observations;

(d) The nomination by a Member of a station in the network implies a clear commitment of the Member concerned to make an effort to carry out the schedule of observations.

2.1.5 Arrangements and procedures for updating and amending the Regional Basic Synoptic Network

Certain minor changes in the RBSN of surface and upper-air stations that do not affect the data requirements of the Region as a whole are inevi table. To provide a simple and rapid means of effecting changes proposed by the Members concerned, the following procedure shall be followed:

(a) The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of RBSN stations without formal consultation with the Members of the Association, it being understood that any change of substance, that is, one adversely affecting the density of the network or proposing a significant change in observational hours, would still require the formal agreement of Members through the adoption of a resolution by postal ballot;

2. REGION II

ASIA

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MANUAL ON THE GLOBAL OBSERVING SYSTEM II-2

II-2

2.2 REGIONAL BASIC CLIMATOLOGICAL NETWORK OF SURFACE AND UPPER-AIR OBSERVING STATIONS 2.2.1 Composition of the Regional

Basic Climatological Network 2.2.1.1 The Regional Basic Climatological Network (RBCN) was established by the Association to provide a comprehensive network of CLIMAT reporting stations. It is based primarily on RBSN stations and includes all Global Climate Observing System (GCOS) Surface Network (GSN) and GCOS Upper-air Network (GUAN) stations, regardless of whether these report CLIMAT or not.

The RBCN also includes all other stations that report CLIMAT needed for description of regional climate features. These other stations should be selected under the same criteria used for GSN stations. Non-RBSN stations reporting CLIMAT messages should be considered, particularly those with long records, as well as any Reference Climatological Stations.

2.2.2 Arrangements and procedures for updating and amending the Regional Basic Climatological Network

The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of RBCN stations without formal consultation with the Members of the Association, following similar procedures to those specified for the RBSN.

2.3 REGIONAL ARRANGEMENTS AND PROCEDURES FOR OBSERVATIONS

2.3.1.1 According to this Manual, Volume I, Part III, Regulation 3.3.2.6, the atmospheric pressure at a station shall be reduced to mean sea level, except at those stations where the resolutions of the Association prescribe otherwise (see the Manual on Codes (WMO-No. 306), Volume II, Region II, Section A.1, 2/12.1.1).

2.3.1.2 The Association has not taken any decision regarding the introduction of a uniform method of pressure reduction throughout the Region, as it considers that a uniform method of pressure reduction could be used only in areas that have similar lapse rates of temperature and humidity in the lower troposphere. On this general principle, it is of the opinion that different formulae may be needed for different climatic areas. A number of selected methods of pressure reduction were consequently elaborated and were included in the Note on the Standardization of Pressure Reduction Methods in the International Network of Synoptic Stations (WMO-No. 154, Technical Note No. 61) (out of print).

2.3.2.1 Each Member in the Region should ensure that the barometer of each observing station in its territory is traceable to a fixed national barometric standard, through an appropriate series of comparisons at least once every three years.

2.3.2.2 National barometric standards should be traceable to an absolute barometric standard

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II-3

REGION II – ASIA II-3

recognized by WMO, within or outside the Region, through an appropriate intercomparison at least every 10 years.

Note: The term “barometric standard” is used rather than “standard barometer”, as often the standard is not a barometer; for example, a dead weight tester is a pressure standard, but not a barometer.

2.3.2.3 The standard barometer in Calcutta (India) shall be recognized as the reference standard barometer for the Region.

2.3.3 Ground weather radar observations Considering the value of ground weather radar observations for forecasting purposes and their essential role in detecting and tracking tropical cyclones, Members that have not yet done so are invited to establish and maintain ground weather radar stations for synoptic and particularly tropical cyclone warning purposes. Weather radars have also demonstrated their usefulness for short-range weather forecasting, in particular for the assessment of area precipitation.

2.3.4 Regional Instrument Centres 2.3.4.1 Considering the need for regular calibration and maintenance of meteorological instruments to meet increasing needs for high-quality meteorological and hydrological data, the requirements of Members in the Region for standardization of meteorological measurements, the need for international instrument comparisons and evaluations, and for train ing of instrument experts, the Regional Instrument Centres should be established according

to the Guide to Meteorological Instruments and Methods of Observ ation (WMO-No. 8), Part I, Chapter 1, Annex 1.A.

2.3.4.2 The instrument centres in Beijing and Tsukuba (Japan) are designated as Regional Instrument Centres.

2.3.5.2 The radiation centres in Pune (India) and Tokyo are designated as Regional Radiation Centres.

A summary of best practices involved in discharging the commitments made by the Member concerned regarding GCOS surface and upper-air stations is included in this Manual, Volume I, Part III, Regulation 2.9 (for GSN stations) and Regulation 2.10 (for GUAN stations).

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3.1.2 Criteria for inclusion of stations in the Regional Basic Synoptic Network 3.1.2.1 Definition of the criteria

For the definition of the criteria, two types of requirements are distinguished:

(a) Target requirements (TRQs) refer to desired characteristics of network stations;

(b) Minimum requirements (MRQs) refer to threshold characteristics which are decisive for inclusion or exclusion of a station.

The inclusion of a station in the network implies a clear commitment by the Member concerned to make fair efforts for (maintaining) compliance with the TRQs.

In the table below, TRQs and MRQs for RBSN stations are recorded.

3.1.2.2 Classification of stations

Stations are classified according to their perform- ance with reference to the requirements in 3.1.2.1 above:

(a) Those stations meeting all TRQs are classified as OK;

(b) Those stations meeting all MRQs are classified as IP (incomplete programme);

(c) Operational stations not meeting all MRQs are classified as BC (below criteria);

(d) Silent stations are classified as NO (not operating).

3. REGION III SOUTH AMERICA

TRQ Surface MRQ Surface TRQ Upper-air MRQ Upper-air Parameters

(measured and recorded) Pressure Temperature Wind Humidity Weather Visibility Cloud cover Cloud base

Pressure Temperature Wind

(not for buoys) Humidity (not for buoys)

Pressure/

Level Surface Surface Up to 10 hPa Up to 100 hPa

Observations at main

hours UTC 4 3 2 (at 0000 and

1200) 1 (at 0000 or 1200) Observations at main and

intermediate hours (i.e., 3 hourly)

8 5 – –

Availability of data 100% 50% 100% 50%

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MANUAL ON THE GLOBAL OBSERVING SYSTEM III-2

III-2

3.1.2.3 Horizontal distribution of surface stations

(a) As an ideal target over land areas, the RBSN should have a horizontal resolution of 150 km for surface and 250 km for upper-air stations;

(b) As an optimal target over land areas, the RBSN should have a horizontal resolution of 250 km for surface and 500 km for upper-air stations;

(c) OK stations are acceptable if at a distance of at least 60 km from the nearest network station.

3.1.2.4 Application of the criteria

The criteria are developed and revised periodically by the Association at each of its sessions, which take place every four years. These criteria should ensure a network with an optimum composition regarding the observing programme, reliability of reception and spacing of stations. In particular, the criteria should allow for the inclusion of stations with reduced observing programmes in data-sparse areas.

3.1.3 Arrangements and procedures for updating and amending the Regional Basic Synoptic Network Certain minor changes in the RBSN of surface and upper-air stations that do not affect the data requirements of the Region as a whole are inevi table. To provide a simple and rapid means of effecting changes proposed by the Members concerned, the following procedure shall be followed:

(a) The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of RBSN stations without formal consultation with the Members of the Association, it being understood that any change of substance, that is, one adversely affecting the density of the network or proposing a significant change in observational hours, would still require the formal agreement of Members through the adoption of a resolution by postal ballot;

(b) The Secretary-General shall notify all Members of WMO through the Operational Newsletter or by circular letter of changes agreed with the president of the Association.

3.2 REGIONAL BASIC CLIMATOLOGICAL NETWORK OF SURFACE AND UPPER-AIR OBSERVING STATIONS 3.2.1 Composition of the

Regional Basic

3.2.1.1 The Regional Basic Climatological Network (RBCN) was established by the Association to provide a comprehensive network of CLIMAT reporting stations. It is based primarily on RBSN stations and includes all Global Climate Observing System (GCOS) Surface Network (GSN) and GCOS Upper-air Network (GUAN) stations, regardless of whether these report CLIMAT or not. The RBCN also includes all other stations that report CLIMAT needed for description of regional climate features, except those that are within 60 km of another network station. These other stations should be selected under the same criteria used for GSN stations.

Non-RBSN stations reporting CLIMAT messages should be considered, particularly those with long records, as well as any Reference Climatological Stations.

The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of RBCN stations without formal consultation with the Members of the Association, following similar procedures to those specified for the RBSN.

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III-3

REGION III – SOUTH AMERICA III-3

appropriate WMO code form, for example, FM 94-XIV BUFR.

3.3.4 Regional Instrument Centres 3.3.4.1 Considering the need for regular calibration and maintenance of meteorological instruments to meet increasing needs for high- quality meteorological and hydrological data, the requirements of Members in the Region for standardization of meteorological measurements, the need for international instrument comparisons and evaluations, and for training of instrument experts, the Regional Instrument Centres should be established according to the Guide to Meteoro

logical Instruments and Methods of Observation (WMO-No. 8), Part I, Chapter 1, Annex 1.A.

3.3.4.2 The Meteorological Laboratory and Workshop of the National Meteorological Service of Argentina in Buenos Aires is designated as the Regional Instrument Centre.

3.3.5.1 Considering the usefulness of the calibration of national and regional standard pyrheliometers against pyrheliometers of the World Standard Group at five-year intervals for guaranteeing the high quality of radiation data and noting Resolution 11 (EC-XXX) – National, Regional and World Radiation Centres, Regional Radiation Centres should be established according to the Guide to Meteorological Instruments and Methods of Observation (WMO-No. 8), Part I, Chapter 7, Annex 7.C.

3.3.5.2 The radiation centres in Buenos Aires, Santiago and Lima are designated as Regional Radiation Centres.

3.4 GLOBAL CLIMATE OBSERVING SYSTEM A summary of best practices involved in discharging the commitments made by the Member concerned regarding GCOS surface and upper-air stations is included in this Manual, Volume I, Part III, Regulation 2.9 (for GSN stations) and Regulation 2.10 (for GUAN stations).

3.3.1.1 According to this Manual, Volume I, Part III, Regulation 3.3.2.6, the atmospheric pressure at a station shall be reduced to mean sea level, except at those stations where the resolutions of the Association prescribe otherwise (see the Manual on Codes (WMO-No. 306), Volume II, Region III, Section A.1, 3/12.1.1).

3.3.1.2 The Association has not taken any decision regarding the introduction of a uniform method of pressure reduction throughout the Region and Members of the Region are free to use the method that suits them best.

Note: The term “barometric standard” is used rather than

“standard barometer”, as often the standard is not a barometer;

for example, a dead weight tester is a pressure standard, but not a barometer.

Considering the usefulness of exchanging, on a bilateral or multilateral basis, meteorological information obtained by ground weather radar stations, Members are urged to continue their efforts to install ground weather radar stations for detecting precipitation, including heavy rain, hail and other severe weather phenomena, and to exchange on a bilateral or multilateral basis the meteorological information so obtained using the

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4.1.2 Surface synoptic observations All surface stations included in the RBSN should make surface observations at the four main standard times of observation, that is, 0000, 0600, 1200 and 1800 UTC, and at the four intermediate standard times of observation, that is, 0300, 0900, 1500 and 2100 UTC. Any surface station that cannot carry out the full observational programme should give priority to carrying out the observations at the main standard times.

4.1.3 Upper-air synoptic observations All upper-air stations included in the RBSN should carry out radiosonde and/or radiowind observations up to the 10 hPa level at 0000 and 1200 UTC.

Stations that are unable to carry out the full observing programme should give priority to the making of observations at 1200 UTC.

4.1.4 Principles to be applied when revising the Regional Basic Synoptic Network

(b) If an RBSN station was “silent” according to monitoring results and another RBSN station located nearby (less than 100 km for surface

stations) had regularly reported its observation, the “silent” station should be replaced in the RBSN. If there is no alternative regularly reporting station nearby, the “silent” station may remain on the list if there is an intention to restore operations;

4.1.5 Arrangements and procedures for updating and amending the Regional Basic Synoptic Network

Certain minor changes in the RBSN of surface and upper-air stations that do not affect the data require ments of the Region as a whole are inevitable. To provide a simple and rapid means of effecting changes proposed by the Members concerned, the following procedure shall be followed:

(a) The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of RBSN stations without formal consultation with the Members of the Association, it being understood that any change of substance, that is, one adversely affecting the density of the network or proposing a significant change in observational hours, would still require the formal agreement of Members through the adoption of a resolution by postal ballot;

4. REGION IV

NORTH AMERICA, CENTRAL AMERICA AND THE CARIBBEAN

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MANUAL ON THE GLOBAL OBSERVING SYSTEM IV-2

IV-2

Basic Climatological Network 4.2.1.1 The Regional Basic Climatological Network (RBCN) was established by the Association to provide a comprehensive network of CLIMAT reporting stations. It is based primarily on RBSN stations and includes all Global Climate Observing System (GCOS) Surface Network (GSN) and GCOS Upper-air Network (GUAN) stations, regardless of whether these report CLIMAT or not. The RBCN also includes all other stations that report CLIMAT needed for description of regional climate features. These other stations should be selected under the same criteria used for GSN stations. Non-RBSN stations reporting CLIMAT messages should be considered, particularly those with long records, as well as any Reference Climatological Stations.

4.2.1.3 Members are urged to comply fully with the global and regional coding procedures and data-collection standards in accordance with procedures laid down in the WMO Technical Regulations (WMO-No. 49), Manual on Codes (WMO-No. 306), Manual on the Global Telecommunication System (WMO-No. 386) and in this Manual when operating the RBCN stations.

The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of RBCN stations without formal consultation with the Members of the Association, following similar procedures to those specified for the RBSN.

According to this Manual, Volume I, Part III, Regulation 3.3.2.6, the atmospheric pressure at a station shall be reduced to mean sea level. However, pending a worldwide decision on a uniform pressure-reduction method, the method being used in the United States of America for reducing atmospheric pressure to mean sea level should be applied in the Region.

4.3.2.1 Each Member in the Region should ensure that the barometer of each observing station in its territory is traceable to a fixed national barometric standard, through an appropriate series of comparisons at least once every two years.

4.3.2.3 The barometric standard at the National Institute of Standards and Technology (NIST), Gaithersburg, Maryland (United States) shall be recognized as the absolute standard for the Region.

4.3.2.4 The barometric standards in Guatemala City, Mexico, D.F., Miami, Florida (United States), San Juan (Puerto Rico), Silver Spring, Maryland (United States) and Toronto (Canada) shall be the subregional standard barometers for the Region.

Notes:

1. The term “barometric standard” is used rather than “standard barometer”, as often the standard is not a barometer, for example, a dead weight tester is a pressure standard, but not a barometer.

2. There is no standard barometer in Washington, D.C. The standard barometer at the National Weather Service Headquar- ters in Silver Spring is not a national standard, but a working standard traceable to NIST.

Meteorological radars are important for both operational and research purposes in synoptic meteorology and hydrology, and in improving the accuracy of short-period forecasts, especially those

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IV-3 REGION IV – NORTH AMERICA, CENTRAL AMERICA AND THE CARIBBEAN IV-3 for aviation, while non-meteorological radars, such

as aircraft surveillance radars, may often be used advantageously for meteorological purposes and thus fill any temporary gaps in the radar network.

Members should therefore take all practical steps to encourage the installation of meteorological radars in their own countries, coordinating, where desirable, with neighbouring countries, and should also make maximum use of non-meteorological radars for meteorological purposes.

4.3.4 Regional Instrument Centres 4.3.4.1 Considering the need for regular calibration and maintenance of meteorological instruments to meet increasing needs for high- quality meteorological and hydrological data, the requirements of Members in the Region for standardization of meteorological measurements, the need for international instrument comparisons and evaluations, and for train ing of instrument experts, the Regional Instrument Centres should be established according to the Guide to Meteorological Instruments and Methods of Observ ation (WMO- No. 8), Part I, Chapter 1, Annex 1.A.

4.3.4.2 The instrument centres at Mount Washing ton, New Hampshire (United States), the Caribbean Institute for Meteorology and Hydrology, Bridgetown and the Regional Training Centre in

San José are designated as Regional Instrument Centres.

4.3.5.2 The radiation centres in Toronto (Canada), Mexico, D.F. and Boulder, Colorado (United States) are designated as Regional Radiation Centres.

4.4 GLOBAL CLIMATE OBSERVING SYSTEM A summary of best practices involved in discharging the commitments made by the Member concerned regarding GCOS surface and upper-air stations is included in this Manual, Volume I, Part III, Regulation 2.9 (for GSN stations) and Regulation 2.10 (for GUAN stations).

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5.1.2 Surface synoptic observations All surface stations included in the RBSN should make surface observations at the four main standard times of observation, that is, 0000, 0600, 1200 and 1800 UTC, and at the four intermediate standard times of observation, that is, 0300, 0900, 1500 and 2100 UTC. Any surface station that cannot carry out the full observational programme should give priority to carrying out the observations at the main standard times.

5.1.3 Upper-air synoptic observations

All upper-air stations included in the RBSN should carry out radiosonde and/or radiowind observations up to the 10 hPa level at 0000 and 1200 UTC. Additional radiowind observations at 0600 and 1800 UTC are also desirable. Any radiosonde station that cannot carry out the full observing programme required should give priority to making the 0000 UTC observations.

5.1.4 Principles to be applied when revising the Regional Basic Synoptic Network

(b) If an RBSN station was “silent” according to monitoring results and another RBSN station located nearby (less than 100 km for surface stations) had regularly reported its observation, the “silent” station should be replaced in the RBSN. If there is no alternative regularly reporting station nearby, the “silent” station may remain on the list if there is an intention to restore operations;

5.1.5 Arrangements and procedures for updating and amending the Regional Basic Synoptic Network Certain minor changes in the RBSN of surface and upper-air stations that do not affect the data requirements of the Region as a whole are inevitable. To provide a simple and rapid means of effecting changes proposed by the Members concerned, the following procedure shall be followed:

(a) The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of RBSN stations without formal consultation with the Members of the Association, it being understood that any change of substance, that is, one adversely affecting the density of the network or proposing a significant change in observational hours, would still require the formal agreement of Members through the adoption of a resolution by postal ballot;

5. REGION V

SOUTH-WEST PACIFIC

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MANUAL ON THE GLOBAL OBSERVING SYSTEM V-2

V-2

Basic Climatological Network 5.2.1.1 The Regional Basic Climatological Network (RBCN) was established by the Association to provide a comprehensive network of CLIMAT reporting stations. It is based primarily on RBSN stations and includes all Global Climate Observing System (GCOS) Surface Network (GSN) and GCOS Upper-air Network (GUAN) stations, regardless of whether these report CLIMAT or not. The RBCN also includes all other stations that report CLIMAT needed for description of regional climate features. These other stations should be selected under the same criteria used for GSN stations.

Non-RBSN stations reporting CLIMAT messages should be considered, particularly those with long records, as well as any Reference Climatological Stations.

5.2.1.2 The RBCN of surface and upper-air observing stations is reviewed and revised at each session of the Association. The list of stations constituting the current RBCN is given in the report of the most recent session of the Association. Changes are announced in the monthly Operational Newsletter issued by the Secretariat (see 5.2.2 below).

5.2.1.4 CLIMAT reports from RBCN stations shall be regarded as essential data in the sense of Resolution 40 (Cg-XII) – WMO policy and practice for the exchange of meteorological and related data and products including guidelines on relationships in commercial meteorological activities.

5.2.2 Arrangements and procedures for updating and amending the Regional Basic Climatological Network

The Association authorizes its president to approve, at the request of the Member concerned, on the advice of the chair of the respective subsidiary body of the Association and in consultation with the Secretary-General, minor amendments to the list of

RBCN stations without formal consultation with the Members of the Association, following similar procedures to those specified for the RBSN.

5.3.1.1 According to this Manual, Volume I, Part III, Regulation 3.3.2.6,the atmospheric pressure at a station shall be reduced to mean sea level, except at those stations where the resolutions of the Association prescribe otherwise (see the Manual on Codes (WMO-No. 306), Volume II, Region V, Section A.1, 5/12.1.1).

5.3.1.2 The Association has not taken any decision regarding the introduction of a uniform method of pressure reduction throughout the Region as it considers that, because of the topogra- phy of the Region and the fact that a large majority of the meteorological stations in the Region have an elevation of less than 300 metres, this is not a matter of great importance.

Note: The term “barometric standard” is used rather than “standard barometer”, as often the standard is not a barometer; for example, a dead weight tester is a pressure standard, but not a barometer.

5.3.2.3 The dead weight tester in the Australian Regional Instrument Centre in Melbourne shall be recognized as the reference standard barometer for the Region.

Considering that ground weather radar observations have demonstrated their usefulness for

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V-3

REGION V – SOUTH-WEST PACIFIC V-3

short-range forecasting, for assessment of precipitation over a given area and for the tracking of tropical cyclones and disturbances, Members that have not yet done so are invited to establish and maintain ground weather radar stations. Members that operate weather radars are encouraged to exchange the data with other Members.

5.3.4 Regional Instrument Centres 5.3.4.1 Considering the need for regular calibration and maintenance of meteorological instruments to meet increasing needs for high- quality meteorological and hydrological data, the requirements of Members in the Region for standardization of meteorological measurements, the need for international instrument comparisons and evaluations, and for training of instrument experts, the Regional Instrument Centres should be established according to the Guide to Meteorological Instruments and Methods of Observation (WMO- No. 8), Part I, Chapter 1, Annex 1.A.

5.3.4.2 The instrument centres in Melbourne (Australia) and Manila are designated as Regional Instrument Centres.

5.3.5.2 The radiation centre in Melbourne (Australia) is designated as the Regional Radiation Centre.

5.4 OTHER IN SITU OBSERVING SYSTEMS 5.4.1 Marine observations

Members are urged to contribute to programmes for the collection of meteorological and oceano- graphic observations over ocean areas.

5.4.2 Aircraft meteorological data relay programme

In order to significantly increase the number of upper-air reports for improved analysis and forecasts, Members of the Association are requested to explore opportunities for obtaining reports from their national airlines as part of regional or sub - regional aircraft meteorological data relay (AMDAR) programmes.

5.4.3 Space-based observations

Members should possess the means to receive and display satellite imagery and quantitative data. For weather forecasting purposes the geostationary satellite imagery is a high priority. Meteorological research satellites are now considered part of the Global Observing System.

5.5.1 Priority should be given by Members of the Association in the implementation of the various components of GCOS such as the GSN, GUAN and the Baseline Surface Radiation Network.

5.5.2 A summary of best practices involved in discharging the commitments made by the Member concerned regarding GCOS surface and upper-air stations is included in this Manual, Volume I, Part III, Regulation 2.9 (for GSN stations) and Regulation 2.10 (for GUAN stations).

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